Abstract: Floating seedlings were used as experimental carriers, the effects of different wasp aphid ratio on the reproduction of A. gifuensis by simultaneous inoculating technology (SIT) were studied. The results showed that the reproductive effect of A. gifuensis was the best when the wasp aphid ratio was 1:100. Under this ratio, the initial parasitic rate of the parasitic aphids was 52.28%. Inoculated 4 parasitic aphids per plant, the amount of aphid mummies reached up to 261.66 per plant and the parasitic rate up to 97.3% after 25 days of rearing. The second best reproductive effect of A. gifuensis was observed when the ratio was 1:200. The third best reproductive effect was observed when the ratio was 1:50. The SIT is suitable for the mass rearing of A. gifuensis, and its effect is better than that of asynchronous inoculating technology (AIT), therefore we suggest that the best wasp aphid ratio range of simultaneous inoculation is 1:100 to 1:200.